DES MOINES, Iowa — A group of conservative lawmakers have proposed cutting the salaries of Iowa Supreme Court justices who joined in a unanimous ruling four years ago that legalized same-sex marriage in Iowa.

Five Republicans filed an amendment to the state House’s judicial branch budget Tuesday that would reduce the salaries of the remaining four justices who joined in the 2009 ruling from about $163,000 annually to $25,000. That’s the pay of legislators, who also receive money for expenses.

Republican Rep. Larry Sheets of Moulton, who is joining four other lawmakers in the effort, acknowledged it’s a longshot, but he said it’s important to draw attention to the ruling.

Sheets said the justices “overstepped their constitutional boundaries” in making a decision that should have been left up to the Legislature. If the justices are going to behave like legislators, they ought to receive lawmakers’ pay, he said.

“The important thing (we’re) trying to do is make a statement that there needs to be separation of powers,” Sheets said.

Gay marriage has been legal in Iowa since the unanimous 2009 state Supreme Court ruling, which found a law limiting marriage to between men and women violated Iowa’s constitution. The measure applies to Chief Justice Mark S. Cady and Justices David S. Wiggins, Daryl L. Hecht and Brent R. Appel, all of whom joined in the decision.

Voters removed three other justices in a 2010 retention election.

Sheets acknowledged the proposal is a longshot that wouldn’t clear the Senate.

Besides having to pass the Legislature, the amendment wouldn’t implement the pay cut until voters approved a constitutional amendment stating that marriage was between a man and a woman. It would take approval of two legislative assemblies elected in consecutive elections before a measure could be referred to voters.

If approved, justices could choose to resign or take a pay cut.

Sen. Robb Hogg, D-Cedar Rapids, called the proposal “ridiculous.”

“It reflects a lack of basic understanding about our system of government,” said Hogg, chairman of the Senate Judiciary Committee. “It is almost certainly unconstitutional to pay different justices different salaries based on when they were appointed to the bench.”

Steve Davies, a spokesman for the Iowa Judicial Branch, declined to comment.

Rep. Dwayne Alons, R-Hull, submitted the amendment.

Last month, Alons introduced a joint resolution signed by 34 other House Republicans proposing a change in the Iowa Constitution to ban gay marriage. It did not survive a self-imposed Legislative deadline.